The Gold Line now goes from Pasadena to East Los Angeles.
The cities of El Monte, Montebello, Monterey Park, Rosemead and South El Monte are collaborating on a plan to extend the rail line east from East L.A., parallel to the 60 Freeway.
A competing plan would have the trains veer into Whittier, to serve a number of dense housing developments.
Cities in the northern San Gabriel Valley have already won an extension from Pasadena east through Montclair, eventually connecting to Ontario International Airport.
